The invention relates to a method and an arrangement for real-time transmission of compressed data.
The transmission of compressed data in the field of telecommunications is usually effected on line-connected connections. Thus, by way of example, video data is generated in the course of a video conference or during video telephony by ISDN terminals (Integrated Services Digital Network) and is transmitted in real time exclusively via circuit-switched connections of an ISDN fixed network with a constant data rate; i.e., on one or two 64 kbit/s paths. Depending on the motion of the objects in the recorded picture, the coding device responsible for the data compression generates data streams with greatly varying data rates. For transmission in the ISDN fixed network, the data streams—with the varying data rates—are brought to the respective constant data rate by the suitable addition of filling data (bit stuffing) to the compressed video data. Real-time transmission of the compressed data, that has been conditioned with filling data, into a communications network with data streams with a variable data rate (e.g., a mobile communications network with a radio interface), is uneconomical since the precious transmission bandwidth available on the radio interface must be utilized as efficiently as possible with regard to useful data transmission.
An object of the present invention is to employ a method and an apparatus by which it is possible to obtain economical real-time transmission of compressed data from one communications network to another communications network.